Increasingly advanced microelectrode systems are required to support the ongoing rapid progress in neuroscience. The experiment-driven pull for better electrode technologies comes from many directions and involves diverse and challenging requirements, including increased numbers of recording sites, implantable systems for long-term monitoring, and drug delivery capabilities. The overall goal of this project is to meet this need through the Center for Neural Communication Technology (CNCT). The Center's charter is two-fold: develop sensors and integrated microsystems for advanced neural interfaces and then translate these technologies into functional probe systems that can be effectively distributed to the general to the neuroscience community. The Center's core resource is a silicon probe technology that has a large design space matched to a mature microfabrication process. The proposed project builds directly on this foundation. The first objective is to conduct four inter-related core research projects that collectively extend the application space of the silicon probes in the directions of chronic systems and integrated drug delivery functionalities. The specific aims include integrating microfabricated flow control components into base probes that have very small fluid channels, developing probe coatings for tissue integration and control of gliosis, developing probe systems for neurochemical microsampling, investigating the fluid dynamics of controlled microinjections into targeted brain areas, and developing array processing techniques for multichannel neural recordings. The second objective involves a sizable service component to work with a group of external collaborators to design and fabricate specialized probe systems for use in their existing investigations. Here, the primary emphasis will be on chronic and fluidic probe systems. The collaborators will be selected based on their interest and experience with the silicon probe technologies, their willingness to actively participate in probe development, and their ability to impact their respective areas. The devices and technologies that result from the core research activities will be available for use by the Center's external collaborators per their particular application requirements. This service component stands to increase the impact of the silicon probe technology on the neuroscience community by providing a strong applications-centered pull on the design and development activities. The third objective involves developing a training component to train new investigators on how to effectively use the Center's probe systems. This training component will include an annual short summer course, as well as a mechanism to allow new users to visit the labs of experienced users. By building on its solid foundation as it goes in strategic new directions, the CNCT is in a strong position to continue to provide a national resource for advanced neuroprobes to meet the relentlessly challenging demands of neuroscience research.